k bryant
Needs a job
Sponsor
Posts: 2911
|
posted July 01, 2008 07:13 PM
 Edited By: k bryant on 1 Jul 2008 20:15
quote:
Should we also include whether the dyno operator is our friend, or just needs more business, geez 
Unfortunetly that is actually a really good point. There's many ways to get the numbers to read the way you think the "customer" wants. Hopefully you can find an operator with his integrity completely intact.
One of the reasons we do so much independant testing for other manufactures, oems, and magazines, is because we really are completely neutral. I don't care what the numbers are. Whatever they are, is whatever they are. But I must admit, I get a chuckle out of reading some of the numbers posted around the industry, on forums, etc. Especially the ones that are "all stock". I guess they just have what we call "Happy Dynos". 
   
|
cls
Expert Class
Posts: 410
|
posted July 02, 2008 04:37 AM
I just happened to run across this yesterday. I have no capacity for such things, but I thought it was interesting. Anything to it?
www.factorypro.com/dyno/true1.html
|
entropy
Moderator
Posts: 8671
|
posted July 02, 2008 05:26 AM
quote:
I just happened to run across this yesterday. I have no capacity for such things, but I thought it was interesting. Anything to it?
www.factorypro.com/dyno/true1.html
yep, sure is.
BUT if you gotta see big numbers, stay with dynojet.
don't get me wrong, i really like DJ as a tool, but for detailed work, the DJ just isn't reproducible enough
I understand that Mr Bryant is WAY more experienced than i will ever be, and in his hands a DJ is prob a good bet.
BUT, most hands are not like his (JC is also pretty damn good).
FP step load teats give very, very reproducible results. DJ pulls vary.
____________
This moderator uses moderation in moderation
|
k bryant
Needs a job
Sponsor
Posts: 2911
|
posted July 02, 2008 08:20 AM
Factory Pro Dyno is an excellent tool and I've known Marc for probably 30 years. He knows his stuff and I highly recommend him and his products/services.
I've said this many times over the years, when you are in the aftermarket segment of engine building, tuning, or making any other performance products, we are almost "obligated" to use the Dynojet product to have some kind of direct comparision to your competition and/or the "accepted" (and I use the word loosely) numbers worldwide. If we use the FP or SuperFlow (though I believe Superflow has a "DJ" scale), we get numbers viewed as " suspect" or low. Same if we use a Superflow engine dyno, same if we use most any other brand dyno.
So essentially, whether we like it or not, the Dynojet Dyno has established widely accepted numbers; good, bad, indifferent. That's the way it is.
That being said, I've always believed that the Dyno is simply another tool used for tuning, building, testing, and that's it. Races are won at race tracks. Performance increases are felt when you ride and personally open the throttle. If you like the feeling of the increase and are satisfied whether it's 1 hp or 100 hp, that's really all that matters at the end of the day. And if you're worried too much about it being good enough, well, that's what Bench Racing is for.
|
lietoome
Needs a job
Posts: 2033
|
posted July 03, 2008 12:58 PM
you guys forgot to mention the color of the bike...
red+ 5hp@sea-level.
7-200hp+ for KawiGreen :P
|
frEEk
Administrator
ummm... yeah
Posts: 9660
|
posted July 05, 2008 07:57 PM
quote:
The basic issue is why some operators choose to what we refer to as "force" the numbers to read higher. SAE is, and always should be the "standard". I have asked several times previously for well known aftermarket companies to come on board and post their opinions as to what their logic is when posting data using STD settings. A common answer may be that their competitors post STD, so it may be the kiss of death for them to post 4% lower figures using SAE. I completely understand the logic of that. Does that make it right or wrong ? Perhaps not. But only if we all use the same basic settings (of which we have more than just STD or SAE as well).
If it were me, i'd simply post both, in a similar method to how imperial/metric numbers are presented
Bike #1: 150 HP std (146HP sae)
|
VincentHill
Needs a life
Posts: 6520
|
posted July 06, 2008 04:58 AM
The DJ vs Factory Pro is like Windows vs Mac or VHS vs Beta! Did I mention like SAE vs STD
____________
Made History @ Daytona and still one fast old man!!
|
marc salvisberg
Parking Attendant
Posts: 21
|
posted July 19, 2008 01:48 PM
Edited By: marc salvisberg on 19 Jul 2008 17:24
http://www.factorypro.com/dyno/true1.html
That pretty much explains what the differences are in the HP numbers are - and, partially, why.
There's "True" and there's, now, "Dynojet" hp -
"True" usually matched up with early chassis dyno's numbers, like the old Hartzell, Servequip and Patraco dynos - so - you can look at old 70's and 80's magazines and see, what's now known as "True" hp.
Dynojet inflated their numbers, to some unpublished, secret amount. Rumor (from ex employees), that there were 3 "inflation" factors involved and they had lost the original DOS source code - so - when they converted to a Windows program, they had to re-estimate the factors (and they indeed seem to be a bit different) - at least that's what they told me.
http://www.factorypro.com/magazine/dynojet_dyno_inflated_hp_reason.html
The problem was, we, as a dyno manufacturer, were unable to do a scientifically correct ""DJ Conversion" factor - as many of the dj dynos seemed to read differently from dj dyno to dj dyno (in my experience) and verified by
http://www.factorypro.com/magazine/mag_cyclecanada_Dynojet_dyno.html
The best I could do is to be within 10% of a dynojet hp number - and that's just not valid enough to claim correctness.
Some other dyno companies decided to wing it and make a "dynojet hp" math channel and let it go at "+/- 10%" accuracy....
And that's why HP numbers in the MC industry are so variable and unreliable - wandering dj's and "other" brands of dyno's "trying" to inflate to that wandering standard.
I try to post most of our dyno charts with "True x 1.15 = djhp"
When people are willing to accept wandering HP numbers as the "standard", nothing will ever change.
I do like the idea of posting "100 dhp (85 True HP)"
The one thing that is disturbing is that the dynojet dynos and their clones all assume "some" blanket "inertia value" for the spinning mass of every vehicle - I can't even calculate the actual dj hp error when doing a yz250 (light crank and light rear wheel) and a stock HD (heavy crank and heavy rear wheel - the yz will read a lot higher than the real error and the HD will read a lot lower error.
The Factory Pro EC997 systems will do Sweep Tests with the correct inertial mass and the bikes will read essentially the same, in Steady State (which doesn't care about "vehicle spinning mass") and in a Controlled Sweep Test (controlled acceleration rate test).
See the problem? If you actually use a "correct" inertial mass value in the software, it's impossible to duplicate a dj number - even if they all read the same.
-
For that matter, taking into account that an engine will produce power in amounts that are related to the acceleration rate, you'd have to essentially have the exact equivalent of an 18" concrete filled dyno roller to even begin to get the same shape of a curve as a dynojet dyno - and to do that, you have to give up the ability to do controlled temp steps and controlled acceleration Sweep Tests.
As far as dyno charts, in my opinion, there should be only "Uncorrected" and "Corrected" HP -
If it's "Corrected", the Correction Standard used should be plainly stated.
On our EC997 dyno charts, "Uncorrected" is even a different color then "Corrected", to prevent confusion.
"SAE"? Which one of the standards?
"STD"? Which std?
Kerry's right though, as long as the customer is happy, it's as good as it needs to be -
and it's since you lived in Sacto at Supertrapp - maybe even 32 years!
Best I can do on Saturday afternoon!
Cheers!
Marc
____________
Marc Salvisberg
|
spdprorcng
Parking Attendant
Posts: 12
|
posted July 19, 2008 03:24 PM
Edited By: spdprorcng on 19 Jul 2008 16:33
Marc, ditto your comments.
I now do mainly road race car stuff, but using Dynojet chassis I just
use "uncorrected" values and use Motec ECU/ADL or similar with
BAP for data logging for hard baro figures. Outside of climate
controlled/sensored engine dyno cells it's all a variable. I won't
even start on the RamAir/fresh air equation, You might remember
me from earlier days of AFM at Sears Point with Vince Costa
doing Yamaha FZR600 R&D . Seems like yesterday but that
was many years ago.
|
|
|
|
|
HOME
NEW TOPIC